1. Field of the Invention
The invention relates to a method and a circuit for removing noise signals from video signals by means of adaptive median filtering.
2. Description of the Related Art
German Patent Application P 43 26 390.9, corresponding to U.S. Pat. No. 5,519,453 (Atty. docket PHD 93-105), proposes a method of removing noise signals from video signals by means of a motion adaptive filtering, in which uniformly distributed noise as well as also pulse noise must be eliminated.
In addition, German Patent DE 40 14 971 A1, corresponding to U.K. Patent GB 2,246,265 (PHD 90-246 GB), discloses a circuit arrangement for median filtering of video signals produced during scanning of a film, by means of which, interferences due to dust and scratches must be reduced.
Characteristic of the interferences and of the efficiency of the method described is a limited local expansion of the interference to a few related picture elements, to one line at a maximum.